1. Field of the Invention
The invention relates to a door lock, more particularly a door lock including an unlocking mechanism that can be operated through an inner latch bolt operator to unlatch a latch bolt mechanism and a deadbolt mechanism simultaneously.
2. Description of the Related Art
To permit a panic exit, it is known to provide a door lock with an unlocking mechanism that can be operated through a latch bolt operator at the inside of a door to unlatch a deadbolt simultaneously with the latch bolt Door locks of the above-mentioned type have existed in various forms. An example of such door locks is disclosed in Taiwanese Utility Model Application No. 88204254 and is shown in FIGS. 1, 2 and 3.
Referring to FIGS. 1-3, a door lock is shown to include a slide plate (A) mounted on an inner support plate (B) and having an upper push member (A1) and a lower push member (A2). When the lower cam (D) is rotated by turning an inner latch operator (E) from a position shown in FIG. 2 to another position shown in FIG. 3 to retract a latch bolt (not shown), the lower push member (A2) is moved upward by the lower cam (D) so that the upper push member (A1) drives an upper cam (F) to turn upward or clockwise for unlatching or retracting a deadbolt (not shown). However, although the upper cam (F) turns from a horizontally lying position shown in FIG. 2 to a vertically extending position shown in FIG. 3 when the inner latch operator (E) is operated, because clearances inevitably exist at the connections between components, it is difficult for the upper cam (F) to turn by an angle equal to or larger than 90 degrees. When the turning angle of the upper cam (F) is smaller than 90 degrees, the deadbolt cannot be retracted completely or sufficiently.
U.S. Pat. No. 4,129,019 discloses a door lock of similar type which also includes a slide plate and upper and lower cams all of which are assembled on two cartridge plates to form a cartridge. While the upper cam therein is turnable by 90 degrees or more, a disadvantage therein is that the door lock cannot be changed conveniently between a configuration for a left-hand door installation and a configuration for a right-hand door installation because the entire cartridge must be detached from a place where it is attached and must be turned inside out for configurational changes.